Telephone.



PATENTED NOV..6, 1906.

R, A. DAVIDSON.

TELEPHONE.

APPLIOATION FILED MAY 14, 1906.

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1 9i Memes ROBERT A. DAVIDSON, OF SANTA CRUZ, CALIFORNIA.

TELEPHONE.

Specification of Letters Patent.

Patented Nov. 6, 1906.

Application filed May 14, 1906, Serial No. 316.711.

To all whom it may concern:

Be it known that 1, ROBERT A. DAVIDSON,- a citizen of the United States,residing at Santa Cruz, in the county of Santa Cruz and State ofCalifornia, have invented new and useful Improvements in Telephones, ofwhich the following is a specification.

This invention relates to certain new and useful improvements intelephones.

The invention has for its object the production of simple, practicable,and efficient means whereby when a subscriber leaves his receiver oflthe hook through inadvertence a signal is transmitted to the centraloffice.

A further object of the invention is to provide means whereby thecentral ofiice upon receiving such a signal may operate means forautomatically opening the talking-circuit or opening thesignaling-circuit to central ofiice, means being also provided wherebysaid circuit maybe automatically closed when the receiver-hook is againpressed down or tll ig subscriber attempts to signal the central 0 cc.

The invention will be hereinafter fully set forth, and particularlypointed out in the claims.

In the accompanying drawing the figure is a diagrammatical viewillustrating my invention.

Referring to the drawing, 10 designates the receiver-hook or switch,which is connected to the main line-wire 11, as shown. The otherline-wire 12 terminates in a pivoted arm 13, which engages a contact 15to close the talking or signaling circuit to wire 16, which in turnterminates in a contact 17. The receiver-hook 10 closes the circuitthrough contact 17 when the receiver has been removed. From wire 16extends a branch 18, forming the coil of an electromagnet 19, the otherend of the magnet-winding being shown as grounded in any suitablemanner, the drawing illustrating the winding as grounded through thecondenser 20. Said magnet 19 serves to attract the armature 21, pivotedadjacent thereto, a spring 22, connected to said armature, serving tohold the same normally away from the magnet and in a position to closethe circuit at contact 15. A second magnet or relay 23 is provided, oneend of the winding thereof terminating in a contact 24, which is engagedby a shoulder 25 of the receiverhook when the receiver is hung thereon,the other end of said winding terminating in a contact 26. A pivoted arm27, connected to the main linewire 12, is arranged to close the circuitto magnet 23 when the armature 21 is attracted by magnet 19. An armature28 is pivoted adjacent magnet 23 said armature being provided with ahooked end 29 to engage the end of armature 21 when the same has beenattracted by its magnet, thus preventing the return thereof throughaction of spring 22.

In practice should the subscriber after having used the telephone failfor any reason to hang up the receiver a signal-current is transmittedthrough contact 17, wire 16, contact 15, and main wire 12. The centraloperator upon recognizing the cause of the signal sends an alternatingor pulsating ringing-current out upon the line, whereupon magnet orrelay 19 is energized and the armature 21 attracted thereto. Thearmature in its movement opens the circuit at 15 and closes the circuitto the second magnet through contact 26, and at the same time the end ofsaid armature passes under the hook 29 of armature 28 and is lockedagainst return movement. The parts remain in this position until thesubscriber replaces the receiver upon the hook or attempts to signal theoperator.

As soon as this takes place the circuit to magnet 23 is completedthrough contact 24, resulting in the attraction of armature 28, therocking of which disengages hook 29 from armature 21, and the latter isreturned to its normal position by spring 22. The talkingcircuit is thusagain closed at 15 and the circuit to magnet 23 opened again at 26.

The advantages and o eration of my improved telephone Will be c ear tothose skilled in the art to which it appertains, and it will beparticularly noted that the same is specially applicable to party-lines,although I do not desire to limit its use to this particular class ofsystems. It Will be observed that I have provided simple and practicablemeans whereby the'failure to replace the receiver is at once detectedand the system at once placed in condition to open at this particularinstrument the talking or signaling circuit until the same is again reuired, said circuit being automatically close by any attempt to use thetelephone.

ICC

From What has been said it will be noted that I have illustrated anddescribed the coil of the magnet as grounded through a condenser; but Ido not desire to limit myself in this respect, as the current may passfrom said coil in any other suitable or preferred manner. The same isequally true of the connections with the relay, as it is possible toconnect the latter to the line in various Ways, and the desired resultcan be thereby obtained without interfering with the normal talking orsignaling circuit or the trans mission of sound therein. In fact, it ispractically impossible to anticipate all of the various ways in whichthe different connections may be made with the linewires; but it will beunderstood that I desire to claim, broadly,

any such connection in which the results herein described are obtained.

I claim as my invention 1. An improvement in telephones comprising atelephone system having a normally controlled by said hook forautomatically closing said circuit after operation of saidcircuit-opening means.

3. An improvement in telephones comprising a telephone system having anormally open talking or signaling circuit, a receiver hook toautomatically close said circuit when the receiver is removed, acircuit-closer nor- 'mally closing said circuit and also controlled bysaid hook, and means independent of said hook and operated from thecentral office for actuating said circuit-closer to open the circuit.

4. An improvement in telephones comprising a telephone system having anormally open talking-circuit, a receiver-hook to automatically closesaid circuit when the receiver is removed, a circuit-closer normallyclosing said circuit, an electromagnet con trolled from the centraloffice, an armature for said 'magnet for operating said circuitcloser tobreak the circuit, and means controlled by said hook for restoring saidcircuitcloser to normal position.

5. An improvement in telephones comprising a telephone system having anormally open talking-circuit, a receiver-hook to automatically closesaidcircuit when the receiver is removed, an independent circuitclosernormally closing said circuit, electromagnetic means for operating saidcircuitcloser to open said circuit independently of said hook, and meanscontrolled by said hook for automatically operating said circuitcloserto close the circuit.

6. An improvement in telephones comprising a telephone system having anormally open talking or signaling circuit, a receiverhook toautomatically close said circuit when the receiver is removed, anelectromagnet,

- one terminal of the Winding of which is provided with a contactadjacent said hook, a circuit-closer normally closing said talking orsignaling circuit, and means for operating said circuit-closer to 0 ensaid circuit and simultaneously connecting the other terminal of saidwinding with said circuit, whereby when the receiver is returned to itshook the circuit will be completed through said magnet.

7. An improvement in telephones comprising a telephone system having anormally open talking or signaling circuit, a receiverhook toautomatically close said circuit when the receiver is removed, twocircuit-closers, one of which normally closes said. talking or signalingcircuit the other being normally open, means for operating saidcircuit-closers to open the circuit through the first mentioned andclose the circuit through the last mentioned, and means controlled bythe re ceiver-hook for permitting the parts to return to their normalpositions.

8. An improvement in telephones comprising a telephone system having anormally open talking-circuit a receiver-hook to automatically closesaid circuit when the receiver is removed, a circuit-closer normallyclosing said circuit, an armature controlling said circuit-closer, amagnet for operating said armature, means for locking said armature frommovement when attracted by said magnet, and means controlled by saidhook for freeing said. armature from said locking means.

9. An improvement in telephones comprising a telephone system having anormally open talking or signaling circuit, a receiverhook toautomatically close said circuit when the receiver is removed, acircuitcloser normally closing said circuit, a second circuit-closer, amagnet in circuit with the last-mentioned circuit-closer, an armaturefor alternately operating said circuit-closers, a magnet controllingsaid armature, and a locking device for said armature controlled by thefirst-mentioned magnet, the circuit to said magnet being controlled bysaid hook.

10. An improvement in telephones comprising a telephone system havinganormally open talking or signaling circuit, a receiverhook toautomatically close said circuit when the receiver is removed, acircuit-closer normally closing said circuit, a second circuitcloser, amagnet in circuit therewith, an armature for alternately operating saidcircuitclosers, a magnet controlling said armature, and a pivoted leverfor engaging the end of the circuit to said magnet being controlled bysaid hook.

In testimony whereof I afiix my signature in presence of two subscribingwitnesses.

ROBERT A. DAVIDSON.

said armature to lock the same in position, i Witnesses: said leverhaving an angular portion forming l L. F. GROVER, an armature for thefirstmentioned magnet, H. B. TOWNE.

